# Note: The code might not be as pretty it could be, since it's written
# in a way that maximizes performance. Methods are inlined and loops are avoided.
class_name UUID extends Node

const BYTE_MASK: int = 0b11111111

static func uuidbin():
	randomize()
  # 16 random bytes with the bytes on index 6 and 8 modified
	return [
randi() & BYTE_MASK, randi() & BYTE_MASK, randi() & BYTE_MASK, randi() & BYTE_MASK,
	randi() & BYTE_MASK, randi() & BYTE_MASK, ((randi() & BYTE_MASK) & 0x0f) | 0x40, randi() & BYTE_MASK,
	((randi() & BYTE_MASK) & 0x3f) | 0x80, randi() & BYTE_MASK, randi() & BYTE_MASK, randi() & BYTE_MASK,
	randi() & BYTE_MASK, randi() & BYTE_MASK, randi() & BYTE_MASK, randi() & BYTE_MASK,
		]

static func uuidbinrng(rng: RandomNumberGenerator):
	rng.randomize()
	return [
rng.randi() & BYTE_MASK, rng.randi() & BYTE_MASK, rng.randi() & BYTE_MASK, rng.randi() & BYTE_MASK,
	rng.randi() & BYTE_MASK, rng.randi() & BYTE_MASK, ((rng.randi() & BYTE_MASK) & 0x0f) | 0x40, rng.randi() & BYTE_MASK,
	((rng.randi() & BYTE_MASK) & 0x3f) | 0x80, rng.randi() & BYTE_MASK, rng.randi() & BYTE_MASK, rng.randi() & BYTE_MASK,
	rng.randi() & BYTE_MASK, rng.randi() & BYTE_MASK, rng.randi() & BYTE_MASK, rng.randi() & BYTE_MASK,
		]

static func v4():
  # 16 random bytes with the bytes on index 6 and 8 modified
	var b = uuidbin()

	return '%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x' % [
	# low
b[0], b[1], b[2], b[3],

	# mid
	b[4], b[5],

	# hi
	b[6], b[7],

	# clock
	b[8], b[9],

	# clock
	b[10], b[11], b[12], b[13], b[14], b[15]
		]
  
static func v4_rng(rng: RandomNumberGenerator):
  # 16 random bytes with the bytes on index 6 and 8 modified
	var b = uuidbinrng(rng)

	return '%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x' % [
	# low
b[0], b[1], b[2], b[3],

	# mid
	b[4], b[5],

	# hi
	b[6], b[7],

	# clock
	b[8], b[9],

	# clock
	b[10], b[11], b[12], b[13], b[14], b[15]
		]
  
var _uuid: Array

func _init(rng := RandomNumberGenerator.new()) -> void:
	_uuid = uuidbinrng(rng)

func as_array() -> Array:
	return _uuid.duplicate()

func as_dict(big_endian := true) -> Dictionary:
	if big_endian:
		return {
		"low"  : (_uuid[0]  << 24) + (_uuid[1]  << 16) + (_uuid[2]  << 8 ) +  _uuid[3],
		"mid"  : (_uuid[4]  << 8 ) +  _uuid[5],
		"hi"   : (_uuid[6]  << 8 ) +  _uuid[7],
		"clock": (_uuid[8]  << 8 ) +  _uuid[9],
		"node" : (_uuid[10] << 40) + (_uuid[11] << 32) + (_uuid[12] << 24) + (_uuid[13] << 16) + (_uuid[14] << 8 ) +  _uuid[15]
}
	else:
		return {
		"low"  : _uuid[0]          + (_uuid[1]  << 8 ) + (_uuid[2]  << 16) + (_uuid[3]  << 24),
		"mid"  : _uuid[4]          + (_uuid[5]  << 8 ),
		"hi"   : _uuid[6]          + (_uuid[7]  << 8 ),
		"clock": _uuid[8]          + (_uuid[9]  << 8 ),
		"node" : _uuid[10]         + (_uuid[11] << 8 ) + (_uuid[12] << 16) + (_uuid[13] << 24) + (_uuid[14] << 32) + (_uuid[15] << 40)
}
	
func as_string() -> String:
	return '%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x' % [
	# low
_uuid[0], _uuid[1], _uuid[2], _uuid[3],

	# mid
	_uuid[4], _uuid[5],

	# hi
	_uuid[6], _uuid[7],

	# clock
	_uuid[8], _uuid[9],

	# node
	_uuid[10], _uuid[11], _uuid[12], _uuid[13], _uuid[14], _uuid[15]
		]
  
func is_equal(other) -> bool:
  # Godot Engine compares Array recursively
  # There's no need for custom comparison here.
	return _uuid == other._uuid
